KR102473473B1 - Magnetocardiography Measuring Apparatus - Google Patents

Abstract

A magnetic field measuring device according to an embodiment of the present invention includes an outer container; an inner container containing a liquid refrigerant and disposed inside the outer container and including a neck portion having a first diameter and a body portion having a second diameter larger than the first diameter; A space between the inner container and the outer container is maintained in a vacuum state, and a SQUID sensor module mounting plate disposed under the inner container; a plurality of SQUID sensor modules mounted under the SQUID sensor module mounting plate; and a 4K heat shield formed of a conductive mesh disposed to surround the SQUID sensor module mounting plate and the plurality of SQUID sensor modules.

Description

Cardiogram measuring device {Magnetocardiography Measuring Apparatus}

The present invention relates to a magnetic field measuring device, and more particularly, to a magnetic field measuring device having a coil in a vacuum.

Magnetocardiography (MCG), which measures magnetic field signals generated from ionic current activity of heart muscle, can be a useful technique for diagnosing heart disease.

Superconducting Quantum Interference Device (SQUID) is an ultra-sensitive sensor that can measure ultra-fine magnetic fields generated from biological activities such as the heart, brain, and nerves. SQUID sensors operate at low temperatures of 4 K or 77 K. The measurement sensitivity is several to several tens of fT/√Hz. To cool the SQUID sensor to a low temperature, liquid nitrogen or liquid helium is generally used. A low-temperature refrigerant storage container capable of storing such a low-temperature refrigerant is required. The low-temperature refrigerant storage container has a double structure, consisting of a helium internal storage container (helium tank) for storing low-temperature refrigerant and an external cylinder (vacuum tank) at room temperature, and a vacuum is maintained between them.

In order to measure high-sensitivity signals, it is advantageous to use a SQUID composed of low-temperature superconductors. Since Nb, a superconducting material used in low-temperature superconducting SQUIDs, has a critical temperature of about 9 K, cooling using liquid helium or a low-temperature freezer is required. It is necessary to optimize the structure, thickness, and installation method of insulation materials to reduce thermal magnetic noise caused by metal insulation materials (superinsulation and thermal shield) installed in the vacuum part of Duar while reducing the evaporation rate of Duar. In addition, since helium gas has a property of easily penetrating through small gaps, high density of glass fiber reinforced plastics used as dua materials is required.

Since the strength of the magnetic signal decreases in inverse proportion to the square of the distance from the magnetic field signal source, it is necessary to minimize the distance between the signal source and the detection coil to improve the SNR. Research on this method was conducted, and a coil-in-vacuum (CIV) SQUID was developed and used in which the detection coil is located outside the helium bath, that is, in the vacuum part.

In the case of a CIV-type SQUID device, a detection coil and a SQUID sensor are placed in a vacuum state. Therefore, only low-temperature refrigerant exists in the helium internal storage container for storing the liquefied refrigerant. Therefore, only the passage through which the refrigerant can be filled exists in the neck of the helium internal storage container. Thus, the diameter of the neck portion can be significantly reduced. Accordingly, heat introduced through the neck portion is reduced, thereby reducing the evaporation rate of the liquefied refrigerant.

As heat penetrates the helium internal storage container, the liquid helium boils and evaporates. At this time, vibration is generated inside the internal storage container by boiling of the liquid. If the detection coil is installed on the external vacuum surface instead of the inside of the internal storage container, the influence of vibration caused by the boiling of liquid helium can be reduced.

In addition, when the detection coil and SQUID are installed in a vacuum, the cooling rate during initial cooling is lower than when they are directly immersed in liquid helium. Physical and chemical damage caused by adsorption and condensation on the surface of the SQUID can be eliminated.

One technical problem to be solved by the present invention is to provide a magnetic field measuring device that can easily replace the SQUID sensor module.

One technical problem to be solved by the present invention is to increase the measurement sensitivity of a sensor device by reducing vibration generated when liquid helium boils. In addition, by installing the sensor in the vacuum part, stress during cooling of the sensor is reduced and physical and chemical reliability is increased.

One technical problem to be solved by the present invention is to provide a cooling device having a neck portion structure of a double wall structure capable of blocking radiant heat.

One technical problem to be solved by the present invention is to provide a neck of a double wall structure in order to provide stability for rotation and tilting of a heavy SQUID sensor module and a liquid helium storage container.

One technical problem to be solved by the present invention is to provide a magnetic field measuring device having a vaporized refrigerant collection tube (He gas return tube) of a coaxial double tube structure.

One technical problem to be solved by the present invention is to provide a cooling device capable of recycling a refrigerant.

One technical problem to be solved by the present invention is to provide an effective cooling method for a SQUID sensor module located in a vacuum.

A magnetic field measuring device according to an embodiment of the present invention includes an outer container; an inner container containing a liquid refrigerant and disposed inside the outer container and including a neck portion having a first diameter and a body portion having a second diameter larger than the first diameter; A space between the inner container and the outer container is maintained in a vacuum state, and a SQUID sensor module mounting plate disposed under the inner container; a plurality of SQUID sensor modules mounted under the SQUID sensor module mounting plate; and a 4K heat shield formed of a conductive mesh disposed to surround the SQUID sensor module mounting plate and the plurality of SQUID sensor modules.

In one embodiment of the present invention, the main heat anchor cooled by the refrigerant and disposed on the lower surface of the inner container (main thermal anchor); a ring-shaped auxiliary heat anchor coupled to a side surface of the SQUID sensor module mounting plate through the 4K heat shield and fixing the 4K heat shield; and a litz wire connecting and cooling the main heat anchor and the auxiliary heat anchor.

In one embodiment of the present invention, the SQUID sensor module mounting plate has a ring-shaped ring concave portion on the lower surface of the side, and the SQUID sensor module mounting plate has the SQUID sensor module mounting plate in the ring concave portion. It includes at least one connecting portion penetrating, and the auxiliary heat anchor is engaged with the ring recessed portion and includes at least one protruding portion protruding to be inserted into the through-hole coupling portion.

In one embodiment of the present invention, the 4K heat shielding unit; an upper 4K heat shield disposed on an upper surface of the SQUID sensor module mounting plate; and a lower 4K heat shield disposed to surround the plurality of SQUID sensor modules, and the auxiliary heat anchor may be coupled to a side surface of the SQUID sensor module mounting plate through the lower 4K heat shield.

In one embodiment of the present invention, the sensor guide rod is mounted on the lower surface of the inner container and extends through the SQUID sensor module mounting plate and guides the vertical motion of the SQUID sensor module mounting plate; and a sensor fixing rod mounted on a lower surface of the inner container and fixed to the SQUID sensor module mounting plate.

In one embodiment of the present invention, the SQUID sensor modules pass through the SQUID sensor module mounting plate and are arranged along the first and second directions, and each of the SQUID sensor modules may extend vertically. It may further include a plurality of heat transfer rods extending parallel to the SQUID sensor modules, the heat transfer rods penetrating the SQUID sensor module mounting plate, and both ends of the heat transfer rods may be respectively connected to the 4K heat shield.

In one embodiment of the present invention, the SQUID sensor modules may be arranged in a matrix form along a first direction and a second direction orthogonal to the first direction. The SQUID sensor module mounting plate is spaced apart from the SQUID sensor modules arranged in the first direction and the SQUID sensor modules arranged in the second direction in the SQUID sensor module mounting plate in the first direction. A trench extending in the direction may be further included.

In one embodiment of the present invention, signal line connection holes connected to the trench, arranged at regular intervals in the first direction, and penetrating the SQUID sensor module mounting plate may be further included.

In one embodiment of the present invention, the SQUID sensor module mounting plate has a ring-shaped ring concave portion on the lower surface of the side, and the SQUID sensor module mounting plate has the SQUID sensor module mounting plate in the ring concave portion. At least one connecting portion penetrating, the auxiliary heat anchor engaging with the ring recessed portion and including at least one protruding portion protruding to be inserted into the connecting portion, the trench disposed on the outermost side in the first direction Can be connected to the connector.

In one embodiment of the present invention, the inner container includes: a neck portion into which a baffle insert is inserted; and a body portion having a diameter greater than that of the neck portion, wherein the neck portion may have a double wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder.

In one embodiment of the present invention, the inner cylinder further includes a plurality of ring protrusions protruding outward of the cylinder, the heat anchors are coupled to each of the ring protrusions, and the ring protrusions are spaced apart from each other, The outer cylinders may be separated from each other with the ring protrusion interposed therebetween.

In one embodiment of the present invention, the neck portion may further include a heat shielding film disposed between the inner cylinder and the outer cylinder.

In one embodiment of the present invention, the outer circumferential surface of the ring protrusion and the inner circumferential surface of the column anchor may be screwed together.

In one embodiment of the present invention, the heat anchors include first to third heat anchors of a washer shape arranged vertically spaced apart from each other on the outside of the neck portion, and the first heat anchors are 120K heat shield The second heat anchor may be connected to an 80K heat shield, the third heat anchor may be connected to a 40K heat shield, and the 40K heat shield may be disposed to surround the 4K heat shield.

In one embodiment of the present invention, each of the first to third column anchors may include a plurality of slits extending in a radial direction.

In one embodiment of the present invention, a refrigerant exhaust tube disposed in the baffle insert and exhausting the vaporized refrigerant; a refrigerant injection tube disposed in the baffle insert and injecting refrigerant; and a condenser connected to the refrigerant exhaust tube and the refrigerant injection tube and condensing the vaporized refrigerant exhausted through the refrigerant injection tube, wherein the refrigerant exhaust tube and the refrigerant injection tube have a coaxial structure, and the refrigerant exhaust Each of the tube and the refrigerant injection tube may be a double tube having an inner tube and an outer tube.

In one embodiment of the present invention, the main heat anchor is formed of oxygen-free copper and includes a first disc, a first upper protrusion protruding from the central axis of the first disc to the upper surface, and a central axis of the first disc. a first heat transfer unit including a first lower protrusion protruding to a lower surface; A second heat transfer comprising a second disc formed of oxygen-free copper, a second upper protrusion protruding from a central axis of the second disc to an upper surface, and a second lower protrusion protruding from a central axis of the second disc to a lower surface. wealth; A third heat transfer comprising a third disc formed of oxygen-free copper, a third upper protrusion protruding from a central axis of the third disc to an upper surface, and a third lower protrusion protruding from a central axis of the third disc to a lower surface. wealth; a fourth heat transfer part formed of oxygen-free copper and including a fourth disc, a fourth upper protrusion protruding from the central axis of the fourth disc to an upper surface, and a plurality of holes in a lower surface from the central axis of the fourth disc; a first thermal expansion control unit formed of an insulator and inserted between the first disc of the first heat transfer unit and the second disc of the second heat transfer unit; and a second thermal expansion controller formed of an insulator and inserted between the third disc of the third heat transfer unit and the fourth disc of the fourth heat transfer unit. The second upper protrusion of the second heat transfer part has a groove for engaging with the first lower protrusion of the first heat transfer part, and the second lower protrusion of the second heat transfer part is engaged with the third upper protrusion of the third heat transfer part. and a groove for coupling the third lower protrusion of the third heat transfer unit to the fourth upper protrusion of the fourth heat transfer unit.

In one embodiment of the present invention, the first thermal expansion control unit: a first insulating body having the same diameter as the diameter of the first disc; a second insulating body part buried in the lower surface of the inner body and having a second diameter larger than the first diameter; and a third insulating body having a third diameter smaller than the second diameter, and the third insulating body may be disposed to surround an outer circumferential surface of the second disc.

In one embodiment of the present invention, the SQUID sensor module mounting plate includes a curved portion, and the curved portion may be disposed to surround the left ventricle of the heart.

In one embodiment of the present invention, the inner container includes: a neck portion into which a baffle insert is inserted; and a body portion having a diameter greater than that of the neck portion, wherein the neck portion includes an inner cylinder portion and an outer cylinder portion disposed to surround the inner cylinder portion, and the inner cylinder portion is composed of auxiliary inner cylinders arranged vertically spaced apart from each other. Separated, each of the heat anchors may be respectively inserted between the separated auxiliary inner cylinders.

In one embodiment of the present invention, each of the heat anchors: a first cylindrical portion of a cylindrical shape; and a washer-shaped first washer portion connected outwardly from the center of the first cylindrical portion, and an outer surface outside the first cylindrical portion may be screwed to an inner surface of a corresponding auxiliary inner cylinder.

In one embodiment of the present invention, further comprising fixing parts including a washer-shaped second washer part and a cylindrical second cylindrical part connected to an inner surface of the second washer part, and a pair of fixing parts are connected to the column It may be disposed on the inner upper surface and the inner lower surface of the first washer portion of the anchor, respectively.

In one embodiment of the present invention, the outer cylindrical portion includes a plurality of auxiliary outer cylindrical portions disposed spaced apart from each other, the auxiliary outer cylindrical portion is arranged to surround the second cylindrical portion of the fixing portion, and the heat shielding film comprises the It may be disposed between the auxiliary outer cylinder and the auxiliary inner cylinder.

In one embodiment of the present invention, each of the heat anchors further includes a washer-shaped auxiliary washer portion connected inwardly from the center of the first cylindrical portion, and the auxiliary washer portion may include a slit formed in an azimuth direction.

In an embodiment of the present invention, each of the SQUID sensor modules includes: a bobbin having a rectangular parallelepiped shape and having a rectangular cross section and having a detection coil mounted thereon; a fixing block connected to the bobbin and fixed by being inserted into a hole formed in the SQUID sensor module mounting plate; A SQUID printed circuit board mounted on at least one surface among upper side surfaces of the bobbin and including a superconducting quantum interference device (SQUID) sensor; and a signal line connection PCB inserted into the fixing block and transmitting a signal detected by the SQUID sensor to an external circuit.

In one embodiment of the present invention, the detection coil may be a differential meter. The detection coil includes: a first differential meter disposed on a first side surface of the rectangular cross section of the bobbin; a second differential meter disposed on a second side surface adjacent to the first side surface of the bobbin; and a third differential meter disposed on a lower surface of the bobbin.

A magnetic field measuring device according to an embodiment of the present invention includes an outer container; and an inner container accommodating a liquid refrigerant and inserted into the outer container, wherein the inner container includes: a neck portion into which a baffle insert is inserted; and a body portion having a diameter greater than that of the neck portion. The neck portion includes an inner cylinder portion and an outer cylinder portion disposed to surround the inner cylinder, and the inner cylinder portion is divided into auxiliary inner cylinders disposed vertically spaced apart from each other, and each of the heat anchors is the separated auxiliary inner cylinder Each can be inserted between them.

In one embodiment of the present invention, each of the heat anchors: a first cylindrical portion of a cylindrical shape; and a washer-shaped first washer portion connected outwardly from the center of the first cylindrical portion, and an outer surface outside the first cylindrical portion may be screwed to an inner surface of a corresponding auxiliary inner cylinder.

SQUID sensor module according to an embodiment of the present invention, the detection coil is mounted and a rectangular parallelepiped bobbin having a rectangular cross section; a fixing block connected to the bobbin and fixed by being inserted into a hole formed in the SQUID sensor module mounting plate; A SQUID printed circuit board mounted on at least one surface among upper side surfaces of the bobbin and including a superconducting quantum interference device (SQUID) sensor; and a signal line connection PCB inserted into the fixing block and transmitting a signal detected by the SQUID sensor to an external circuit.

In one embodiment of the present invention, the detection coil is a differential meter, and the detection coil includes: a first differential meter disposed on a first side of the bobbin having first to fourth sides; a second differential meter disposed on a second side surface adjacent to the first side surface of the bobbin; and a third differential meter disposed on a lower surface of the bobbin.

In one embodiment of the present invention, the bobbin includes: a lower bobbin of a rectangular parallelepiped shape; an upper bobbin vertically aligned with the lower bobbin; and bobbin connecting posts respectively disposed at four corners in a vertically extending direction.

The magnetic field measuring device according to an embodiment of the present invention can easily replace the SQUID sensor module.

The magnetic field measuring device according to an embodiment of the present invention can efficiently block radiant heat by using the double-walled neck.

The magnetic field measuring device according to an embodiment of the present invention may block the penetration of the refrigerant into the vacuum layer by using the double-walled neck.

The magnetic field measuring device according to an embodiment of the present invention can improve sensor cooling and effectively reduce the liquid helium evaporation rate by directly contacting the heat anchor mounted on the neck of the double wall structure with the vaporized refrigerant.

In the magnetic field measurement device according to an embodiment of the present invention, vibration can be reduced by installing the detection coil on the lower surface of the vacuum layer of the inner container.

In the magnetic field measuring device according to an embodiment of the present invention, operation reliability may be increased by installing the detection coil and the SQUID on the lower surface of the vacuum layer of the inner container.

The magnetic field measuring device according to an embodiment of the present invention may increase the efficiency of the condenser or cooler by transferring cold helium gas evaporated from the DUA to the condenser using a coaxial double tube structure connecting the condenser and the DUA.

The magnetic field measuring device according to an embodiment of the present invention employs a vacuum-in-coil structure to reduce the distance between the SQUID sensor and the current source, thereby increasing the signal-to-noise ratio.

The magnetic field measuring device according to an embodiment of the present invention may increase measurement accuracy of a signal source by using a 3-axis differential meter.

A magnetic field measuring device according to an embodiment of the present invention includes a main column anchor for cooling a SQUID sensor on a lower surface of an inner container storing a refrigerant. The main thermal anchor is composed of a plurality of parts to increase the thermal contact area while suppressing damage to the inner container due to thermal contraction, thereby efficiently cooling the SQUID sensor through the Litz wire.

1 and 2 are conceptual views illustrating a magnetic field measuring device according to an embodiment of the present invention.
3 is a plan view of the lower surface of the inner container in the magnetic field measuring device of FIG. 1;
4 is a perspective view illustrating a thermal anchor of the magnetic field measuring device of FIG. 1;
Figure 5a is a top plan view of the SQUID sensor module mounting plate of the magnetic field measuring device of FIG.
Figure 5b is a bottom plan view of the SQUID sensor module mounting plate of the magnetic field measuring device of FIG.
6 is a cross-sectional view taken along the line A-A' of FIG. 5A.
7 is a cross-sectional view taken along line BB' of FIG. 5A.
8 is a cross-sectional view taken along line C-C' of FIG. 5A.
9 is a perspective view illustrating the auxiliary heat anchor of FIG. 1;
10 is a cross-sectional view showing a main heat anchor according to an embodiment of the present invention.
11 is a conceptual diagram illustrating a magnetic field measuring device according to another embodiment of the present invention.
12 is a perspective view illustrating the SQUID sensor mounting plate of FIG. 11;
13 is a conceptual diagram illustrating a magnetic field measuring device according to another embodiment of the present invention.
14 is a cross-sectional view illustrating the magnetic field measuring device of FIG. 13 .
15 is a perspective view illustrating a SQUID sensor module according to an embodiment of the present invention.
16 is a perspective view illustrating a detection coil of a differential meter of the SQUID sensor module of FIG. 15;

According to one embodiment of the present invention, a technique of directly re-condensing helium gas into a refrigerator and returning it to the dua is applied. Since self- and vibrational noise caused by the refrigerator and the refrigerant delivery tube are very large, a special dewar structure and SQUID arrangement method are required to prevent the SQUID device from reacting to these vibrations.

With the recent rise in the price of helium gas, a technology for immediately re-condensing helium gas into a refrigerator and returning it to the DUA is required. Vaporized helium is supplied to the refrigerator through the gas exhaust tube, and liquid refrigerant is supplied to the Dua through the refrigerant injection tube. When the gas exhaust tube and the refrigerant injection tube are composed of a single pipe, the refrigerant inside the pipe cannot maintain a cold state due to heat exchange between the inside and outside of the pipe.

The vacuum-in-coil (CIV) SQUID device according to an embodiment of the present invention uses a coaxial double tube structure to solve ice condensation on the baffle insert lid. Each of the exhaust tube of the gas from which the refrigerant is evaporated and the refrigerant injection tube has a double tube structure. The double tube structure may increase cooling efficiency by transferring cold vaporized gas to a cooler, and may enable rotation and tilt posture control of the dua.

In a coil-in-vacuum (CIV) SQUID device, the dua includes an inner container and an outer container surrounding the inner container. However, the inner container absorbs radiant heat from the outside, increasing refrigerant consumption.

In the vacuum-in-coil (CIV) SQUID device according to an embodiment of the present invention, the dua uses a double wall structure in the neck of the inner container into which the baffle insert is inserted. This double-walled structure can greatly contribute to preventing vacuum breakage due to thermal contraction of parts constituting the inside of Dua during rapid cooling. In addition, the double wall structure automatically forms a vacuum layer when the inside of the dua is cooled, and greatly reduces the inflow of radiant heat from the dua neck by disposing a heat shielding film between the double walls to reduce the inflow of radiant heat. In addition, the double vacuum layer can reduce the evaporation rate of liquid helium by improving the vacuum level of the vacuum layer by double blocking the fine helium gas penetrating the epoxy reinforced with glass fibers. In the double wall construction, heat anchors are inserted inside the inner container for efficient thermal contact with the vaporized refrigerant. To reduce damage caused by expansion between the heat anchor and the inner container, the heat anchor and the inner container are screwed together. In addition, the heat anchor inserted into the double wall structure has several holes to increase the thermal contact surface, and efficiently uses waste heat by directly contacting the vaporized refrigerant. Therefore, the effect of the thermal barrier layer is maximized to reduce the evaporation rate of the refrigerant, and at the same time, it is possible to stably support the high-load inner structure, so that noise caused by evaporation of the refrigerant and external vibration can be suppressed.

A cardiogram device according to an embodiment of the present invention employs a coil-in-vacuum (CIV) SQUID that facilitates maintenance of the SQUID sensor, and includes a low-temperature cooling shielding structure to surround the SQUID sensors. . The low-temperature cooling shield structure may be disassembled from each other to facilitate maintenance of the SQUID sensor.

Since the strength of the magnetic signal from the magnetic field signal source decreases in inverse proportion to the square of the distance, it is necessary to minimize the distance between the signal source and the detection coil to improve the signal-to-noise ratio. However, if the interval between the signal source and the detection coil is too narrow, the evaporation rate of the refrigerant may increase. Therefore, a device capable of adjusting the distance between the signal source and the detection coil is required. The present invention can easily adjust the distance between the signal source and the detection coil.

A magnetic cardiogram device according to an embodiment of the present invention includes a main heat anchor disposed on a lower surface of an inner container, and the main heat anchor includes a plurality of heat transfer parts screwed together and heat between the heat transfer part and the inner container. It includes a thermal expansion controller made of an insulating material that controls seal breakage due to expansion. When a plurality of heat transfer units are coupled, a pair of thermal expansion control units buried in the outer and inner surfaces of the inner container are pressed to suppress component damage due to sealing and thermal expansion.

The SQUID sensor module according to an embodiment of the present invention includes a three-axis differential meter and has a structure in which a volume is minimized to reduce heat capacity. For this purpose, the differential system is placed on the bobbin of the cuboid. The bobbin includes an upper bobbin, a lower bobbin, and a bobbin connecting column connecting them. In addition, each differential meter constituting the three-axis differential meter includes a signal coil and a reference coil. Differential meters are arranged on different sides of a cuboid so as to minimize interference with each other within one bobbin and do not cross each other.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete, and the spirit of the present invention will be sufficiently conveyed to those skilled in the art. In the drawings, elements are exaggerated for clarity. Parts designated with like reference numerals throughout the specification indicate like elements.

1 and 2 are conceptual views illustrating a magnetic field measuring device according to an embodiment of the present invention.

3 is a plan view of the lower surface of the inner container in the magnetic field measuring device of FIG. 1;

4 is a perspective view illustrating a thermal anchor of the magnetic field measuring device of FIG. 1;

Figure 5a is a top plan view of the SQUID sensor module mounting plate of the magnetic field measuring device of FIG.

Figure 5b is a bottom plan view of the SQUID sensor module mounting plate of the magnetic field measuring device of FIG.

6 is a cross-sectional view taken along the line A-A′ of FIG. 5A.

7 is a cross-sectional view taken along line BB′ of FIG. 5A.

8 is a cross-sectional view taken along line C-C′ of FIG. 5A.

9 is a perspective view illustrating the auxiliary heat anchor of FIG. 1;

1 to 9, the magnetic field measuring device 100 includes an outer container 110; An inner container containing a liquid refrigerant 30 and disposed inside the outer container 110 and including a neck portion 162 having a first diameter and a body portion 164 having a second diameter larger than the first diameter. (160); A space between the inner container 160 and the outer container 110 is maintained in a vacuum state, and a SQUID sensor module mounting plate 120 disposed under the inner container 160; A plurality of SQUID sensor modules 10 mounted under the SQUID sensor module mounting plate 120; and a 4K heat shield 140 formed of a conductive mesh disposed to surround the SQUID sensor module mounting plate 120 and the plurality of SQUID sensor modules 10 .

The outer container 110 has a cylindrical shape and may be a glass fiber reinforced plastic such as G10 epoxy. The outer container 110 may include an outer container top plate 111 .

The inner container 160 may store the liquid refrigerant 30 and cool the SQUID sensor module 10 through the main heat anchor 170 and the Litz wire 22 . The material of the inner container 160 may be glass fiber reinforced plastic such as G10 epoxy. The interior 160 includes a neck portion 162 into which the baffle insert 150 is inserted; A body portion 164 having a diameter greater than that of the neck portion 162 may be included. The neck portion 162 may have a double wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder. The neck portion 162 may include an inner cylinder 162a and an outer cylinder 162b surrounding the inner cylinder 162a. A heat shielding film 162c may be disposed between the inner cylinder 162a and the outer cylinder 162b. The heat shielding film 162c may have a multilayer structure in which a metal thin film layer having high reflectivity and low emissivity and a very thin nonwoven fabric having low thermal conductivity are sequentially stacked.

The inner cylinder 162a may further include a plurality of ring protrusions 162a′ protruding outward of the cylinder. The ring protrusion 162a' has a cylindrical ring shape and may be integrally formed with the inner cylinder 162a. A screw for screw coupling may be formed on an outer circumferential surface of the ring protrusion 162a′.

The heat anchors 106a to c may be coupled to each of the ring protrusions 162a'. The ring protrusions 162a' are spaced apart from each other, and the outer cylinders 162b may be separated from each other with the ring protrusions 162a' interposed therebetween. An outer circumferential surface of the ring protrusion 162a' and an inner circumferential surface of the column anchors 106a to c may be screwed together.

The ring protrusions 162a′ may be spaced apart from each other. The outer cylinders 162b may be separated from each other with the ring protrusions 162a' interposed therebetween. That is, the outer cylinder 162b may include a plurality of cylindrical parts separated from each other. The distance between the outer cylinder 162b and the inner cylinder 162a may be within several mm. Each of the outer cylinders 162a may include a heat anchor coupling portion 106a`` and a jaw 162b′ surrounding the ring protrusion 162a′. After the outer cylinder 162b is coupled to surround the ring protrusion, the coupled portion may be fixed and sealed with an adhesive such as epoxy.

The heat anchors 106a to c may include first to third heat anchors 106a to c having a washer shape that are vertically spaced apart from each other and sequentially arranged on the outside of the neck. Each of the first to third column anchors 106a to c may include a plurality of slits 108 extending in a radial direction.

The first heat anchor 106a is connected to a 120K heat shield 107a, the second heat anchor 106b is connected to an 80K heat shield 107b, and the third heat anchor 106c is a 40K heat shield (107c). The 40K heat shielding film 107c may be disposed to surround the 4K heat shielding part 140 . The 80K heat shielding film 107b may be disposed to surround the 40K heat shielding film 107c. The 120K heat shielding film 107a may be disposed to surround the 80K heat shielding film 107b.

The heat anchors 106a, 106b, and 106c may be coupled to the ring protrusions 162a′, respectively. An outer circumferential surface of the ring protrusion 162a′ and an inner circumferential surface of the heat anchors 106a, 106b, and 106c may be screwed together. Each of the heat anchors 106a, 106b, and 106c may have a circular washer shape. The thermal enclosures may be copper or aluminum.

The heat anchor 106a may include a cylindrical heat anchor coupling portion 106a`` and a disc-shaped heat anchor body portion 106a`` disposed on an outer circumferential surface of the heat anchor coupling portion. An inner circumferential surface of the heat anchor coupling part 106a`` may be screwed into an outer circumferential surface of the ring protruding part. Accordingly, the heat anchors 106a, 106b, and 106c can be cooled by being in thermal contact with each other over a large area while being stably fixed to the inner container. Screw coupling between the ring protrusion 162a′ and the thermal anchor 106a may improve mechanical stability while providing efficient thermal contact by thermal expansion.

The double wall structure may block the inflow of radiant heat into the inner container 160 from the outside. When the inner container is cooled by a refrigerant, a vacuum may be maintained in a space between the inner cylinder and the outer cylinder. Accordingly, the inflow of heat due to heat transfer is blocked, and the heat shielding film 162c may additionally block the inflow of radiant heat. Accordingly, the neck of the double wall structure may provide higher mechanical stability and higher heat shielding efficiency than the neck of the single wall structure.

The thermal anchors 106a, 106b, and 106c may include first to third thermal anchors 106a, 106b, and 106c sequentially disposed. The first heat anchor 106a may be disposed on the uppermost side of the neck portion 362 and connected to the 120K heat shield 107a. The second heat anchor 106b may be disposed below the first heat anchor 106a and connected to the 80K heat shielding film 107b. The third thermal anchor 106c may be disposed below the second thermal anchor 106b and connected to the 40K thermal shielding film 107b. The outer diameter of the first row anchor 106a may be larger than that of the second row anchor 106b.

The first heat anchor 106a is farthest from the refrigerant and maintained at the highest temperature, and the third heat anchor 106c is closest to the refrigerant and maintained at the lowest temperature. The first to third heat anchors 106a, 106b, and 106c may be cooled by thermal contact with the vaporized refrigerant.

The 40K heat shielding film 107c is coupled to the outer circumferential surface of the third heat anchor 106c and disposed to surround the inner container 160, and may block the inflow of radiant heat. The 40K heat shielding film 107c may include a metal mesh interwoven with metal wires insulated from each other and a heat insulating film. The 40K heat shielding film 107c may cover the 4K heat shielding film.

The 80K heat shielding film 107b is coupled to the outer circumferential surface of the second heat anchor 106b and disposed to surround the 40K heat shielding film 107c, and may block the inflow of radiant heat. The 80K heat shielding film 107b may include a metal mesh interwoven with metal wires insulated from each other and a heat insulating film. The 80K heat shielding film 107b may cover the 4K heat shielding film.

The 120K heat shielding film 107a is coupled to the outer circumferential surface of the first heat anchor 106a and disposed to surround the 80K heat shielding film 107b, and may block an inflow of radiant heat. The 120K heat shielding film 107a may include a metal mesh and a heat insulating film woven of metal wires insulated from each other. The 120K heat shielding film 107a may cover the 80K heat shielding film 107b.

A space between the inner container 160 and the outer container 110 may be maintained in a vacuum state. The outer container lid 111 may include an exhaust port 111a connected to a vacuum pump. The exhaust port 111a may be formed of a G-10 epoxy tube. The lower surface 164a of the body portion 164 may include a plurality of getter grooves. A getter for collecting residual gas in a vacuum state may be disposed in the getter groove.

The baffle insert 150 may be inserted into and disposed in the neck portion 162 of the inner container 160 . The baffle insert 150 may include an insert top plate 151, a baffle 156 disposed under the insert top plate, and a plurality of guide rods 154 supporting the baffle 156 and fixed to the insert top plate. can

The insert top plate 151 has a disc shape and may be formed of G-10 epoxy. The insert top plate 151 may be fixed to the outer container lid 111 . The guide rod 154 is made of G-10 epoxy and may have a rod shape or a pipe shape. The guide rod 154 may support the baffle 156 . The baffle 156 may include styrofoam having high heat retention and a conductive plate. The conductive plate may include an aluminum-coated mylar layer and a copper layer sequentially stacked to block radiant heat.

The refrigerant exhaust tube 153 may be disposed on the insert top plate 151 of the baffle insert 150 and exhaust the vaporized refrigerant. The refrigerant injection tube 152 may be disposed on the insert top plate 151 of the baffle insert 150 and inject refrigerant. Each of the refrigerant exhaust tube 153 and the refrigerant injection tube 152 may be a double tube having an inner tube and an outer tube. In the double tube, the space between the inner tube and the outer tube may maintain a vacuum state during cooling. The refrigerant injection tube 152 may have a coaxial structure inserted into the refrigerant exhaust tube 153 . The refrigerant exhaust tube 153 and the refrigerant injection tube 152 may be formed of G-10 epoxy.

The coaxial double tubes 152 and 153 reduce thermal contact with the insert top plate 151 to reduce ice generation of the insert top plate 151 . When the refrigerant exhaust tube and the refrigerant injection tube are single tubes, the insert top plate 151 and the refrigerant exhaust tube create ice, and the ice seals the outer container lid 111 and the insert top plate 151. and can increase external heat input. The coaxial double tubes 152 and 153 may be disposed on the central axis of the insert top plate 151 . One end of the refrigerant exhaust tube 153 may be disposed at a higher position than the first heat anchor 106a.

The condenser 159 is connected to the refrigerant exhaust tube 153 and the refrigerant injection tube 152 and may condense the vaporized refrigerant exhausted through the refrigerant injection tube 153 . The condenser 159 may be disposed outside the magnetic shield room.

The signal line connection box may be disposed outside the outer container and connect the signal lines 15 of the SQUID sensor.

Main thermal anchors 170 are cooled by the refrigerant and may be disposed at regular intervals on a predetermined circumference on the lower surface of the inner container 160 . The number of main column anchors 170 may be six.

10 is a cross-sectional view showing a main heat anchor according to an embodiment of the present invention.

Referring to FIG. 10, the main heat anchor 170 includes a first heat transfer unit 171, a second heat transfer unit 172, a third heat transfer unit 173, a fourth heat transfer unit 174, and a fifth heat transfer unit. It may include a unit 175 , a first thermal expansion control unit 176 , and a second thermal expansion control unit 177 . The main heat anchor 170 is composed of a plurality of parts, so that the litz wire 2 and the SQUID sensor can be efficiently cooled by increasing the thermal contact area while suppressing damage to the inner container due to thermal expansion.

The first thermal expansion control unit 176 is coupled to a double groove having two radii formed inside the lower surface of the inner container, and the second thermal expansion control unit 177 is formed on the outer side of the lower surface of the inner container. It can be combined into a double groove with two radii.

The first heat transfer unit 171 may include a first disc 171a formed of oxygen-free copper and a first lower protrusion 171b protruding from a central axis of the first disc to a lower surface. The first heat transfer unit 171 may further include a first upper protrusion 171c protruding from the central axis of the first disc to the upper surface.

The second heat transfer part 172 is formed of oxygen-free copper and includes a second disc 172a, a second upper protrusion 172b protruding from the central axis of the second disc to the upper surface, and a lower portion from the central axis of the second disc. A second lower protrusion 172c protruding toward the surface may be included. The second upper protrusion 172b of the second heat transfer part 172 may have a screw groove 172d to be coupled with the first lower protrusion 171b of the first heat transfer part 171 . The second lower protrusion 172c of the second heat transfer part 172 may have a screw groove 172e to be coupled with the third upper protrusion 173b of the third heat transfer part 173 .

The third heat transfer part 173 is formed of oxygen-free copper and includes a third disc 173a, a third upper protrusion 173b protruding from the central axis of the third disc to the upper surface, and a lower portion from the central axis of the third disc. A third lower protrusion 173c protruding toward the surface may be included. The third lower protrusion 173c of the third heat transfer part 173 may have a screw groove 173d to be coupled with the fourth upper protrusion 174b of the fourth heat transfer part 174 .

The fourth heat transfer part 174 is formed of oxygen-free copper and includes a fourth disc, a fourth upper protrusion 174b protruding from the central axis of the fourth disc to the upper surface, and a lower surface from the central axis of the fourth disc. It may include a fourth lower protrusion 174c protruding as

The fifth heat transfer unit 175 may be formed of oxygen-free copper and may include a disc. The fifth heat transfer part 175 may be coupled to the fourth lower protrusion 174c of the fourth heat transfer part 174 . A lower surface of the fifth heat transfer unit 175 may be coupled to the fixing unit 178 . The fixing means 178 may fix and cool the litz wire 22 .

The first thermal expansion controller 176 is formed of an insulator and may be inserted between the first disc 171a of the first heat transfer unit 171 and the second disc 172b of the second heat transfer unit 172. . The first thermal expansion controller 176 may be made of the same material as that of the inner container.

The second thermal expansion control unit 177 is formed of an insulator and may be inserted between the third disc 173a of the third heat transfer unit 173 and the fourth disc 174a of the fourth heat transfer unit 174. . The second thermal expansion controller 177 may be made of the same material as that of the inner container.

The first thermal expansion control unit 176 includes a first insulating body portion 176a having the same diameter as the first diameter D1 of the first disc 171a; a second insulating body portion (176b) buried in the lower surface of the inner body and having a second diameter (D2) larger than the first diameter (D1); and a third insulating body portion 176c having a third diameter D3 smaller than the second diameter D2. The third insulating body portion 176c may be disposed to surround an outer circumferential surface of the second disc 172a. An outer circumferential surface of the third insulating body portion 176c may have a screw groove.

The second thermal expansion controller 177 may have the same structure as the first thermal expansion controller 176 .

When the first to fourth heat transfer units 171 to 174 are coupled to each other, the first thermal expansion control unit 176 and the second thermal expansion control unit 177 may be pressed and sealed with the inner container. In addition, the first disc 171a and the fourth disc 174a may be sealed by pressing the first thermal expansion control unit 176 and the second thermal expansion control unit 177 .

The main heat anchor 170 may cool the 4K heat shield and the SQUID sensor modules 10 through a Litz wire.

Again, referring to FIG. 1, the sensor guide rod 180a is mounted on the lower surface 164a of the inner container and extends through the SQUID sensor module mounting plate 120, and the SQUID sensor module mounting plate 120 can guide the vertical motion of The sensor guide rod 180a may be periodically disposed on a circumference of a constant radius on the lower surface 164a of the inner container.

The sensor fixing rod 180b may be mounted on the lower surface 164a of the inner container and fixed to the SQUID sensor module mounting plate 120 . The sensor fixing bar 180b may be periodically arranged on a circumference of a constant radius on the lower surface 164a of the inner container. The distance between the magnetic field signal source and the detection coil may be adjusted by adjusting the length or fixing position of the sensor fixing bar 180b.

The SQUID sensor module mounting plate 120 has a disc shape and may be made of a non-magnetic material such as G10 epoxy. The SQUID sensor module mounting plate 120 may have a ring-shaped ring recessed portion 120a on a lower surface of its side surface. The SQUID sensor module mounting plate 120 may include at least one connection portion 123 penetrating the SQUID sensor module mounting plate 120 at the ring depression 120a.

The SQUID sensor modules 10 pass through the SQUID sensor module mounting plate 120 and may be arranged in a first direction (x-axis direction) and a second direction (y-axis direction). Each of the SQUID sensor modules 10 may extend vertically. Specifically, the SQUID sensor modules 10 may be arranged in a matrix form along the first and second directions. The upper surface of the SQUID sensor module mounting plate 120 is between the SQUID sensor modules arranged in the first direction and the SQUID sensor modules spaced apart from each other in the second direction and arranged in the first direction. The mounting plate may include a trench 121 extending in the first direction. The signal line connection holes 122 are connected to the trench 121 and are arranged at regular intervals in the first direction and may pass through the SQUID sensor module mounting plate 120 . The signal line connection hole 122 and the trench 121 may provide connection paths for signal lines of a plurality of SQUID sensors constituting the SQUID sensor module.

The auxiliary column anchor 144 is engaged with the ring recessed portion 120a and includes at least one protrusion 144c protruding to be inserted into the coupling portion 123, disposed on the outermost side in the first direction Trench 121 may be connected to the thermal coupling part 123 .

The auxiliary heat anchor 144 may have a ring shape coupled to the side surface of the SQUID sensor module mounting plate 120 through the 4K heat shield 140 and fixing the 4K heat shield 140 . The auxiliary heat anchor 144 may cool the 4K heat shield by making thermal contact with the 4K heat shield. The auxiliary heat anchor 144 is formed of acidless copper and is separated into a semicircular first auxiliary heat anchor 150a and a second auxiliary heat anchor 150b to suppress the flow of vortex.

The 4K heat shield 140 includes an upper 4K heat shield 140a disposed on an upper surface of the SQUID sensor module mounting plate 120; and a lower 4K heat shield 140b disposed to surround the plurality of SQUID sensor modules. The auxiliary heat anchor 144 may be coupled to the side surface of the SQUID sensor module mounting plate through the lower 4K heat shield 140b. The lower 4K heat shield 140b may be disposed to surround the 4K heat shield housing 140c. The 4K heat shield housing 140c may be made of a thin plastic material. The 4K heat shield housing 140c may have at least one opening for vacuum exhaustion. The 4K heat shield housing 140c may extend in a vertical direction to have a small diameter in an area where the SQUID sensor modules 10 are disposed and have a chin in order to reduce a cooling space.

A plurality of heat transfer fixing parts 186 may be periodically mounted along the edge of the SQUID sensor module mounting plate 120 . The heat transfer fixing parts 186 may be made of a metal having a high heat transfer rate, such as acid-free copper. The plurality of heat transfer fixing parts 186 are in thermal contact with the main heat anchor 170 through Litz wire, and are cooled while fixing the upper 4K heat shield 140a, and are attached to the SQUID sensor module mounting plate 120. can be fixed For example, one main heat anchor 170 may be connected to a plurality of heat transfer fixtures 186 through Litz wires. The litz wire 22 may include a plurality of flexible copper conductors.

A plurality of heat transfer rods 20 may be fixed to the SQUID sensor module mounting plate 120 and extend parallel to the SQUID sensor modules 10 . A plurality of heat transfer rods 20 may be arranged in a matrix form. The heat transfer rods 20 may pass through the SQUID sensor module mounting plate 120, and both ends of the heat transfer rods 29 may be connected to and fixed in thermal contact with the 4K heat shield 140, respectively.

Each of the plurality of SQUID sensor modules 10 is cooled by the 4K heat shield 140 . The space between the outer container 110 and the inner container 160 is in a vacuum state. The magnetic field measuring device 100 measures an electrocardiogram and may be disposed inside a magnetic shield room.

If some of the SQUID sensor modules 10 are out of order, the SQUID sensor modules 10 may be separated and replaced. To this end, after the auxiliary heat anchor 144 is removed from the SQUID sensor module mounting plate 120, the 4K heat shield 140 may be removed. Accordingly, a malfunctioning SQUID sensor module can be easily replaced.

11 is a conceptual diagram illustrating a magnetic field measuring device according to another embodiment of the present invention.

12 is a perspective view illustrating the SQUID sensor mounting plate of FIG. 11;

11 and 12, the magnetic field measuring device 200 includes an outer container 210; An inner container containing a liquid refrigerant 30 and disposed inside the outer container 210 and including a neck portion 162 having a first diameter and a body portion 164 having a second diameter larger than the first diameter. (160); A SQUID sensor module mounting plate 220 disposed in a space maintained in a vacuum state between the inner container 160 and the outer container 210; A plurality of SQUID sensor modules 10 mounted under the SQUID sensor module mounting plate 220; and a 4K heat shield 240 formed of a conductive mesh arranged to surround the SQUID sensor module mounting plate 220 and the plurality of SQUID sensor modules 10 .

The upper part of the outer container 210 is cylindrical, but the lower part may be curved so as to surround a part of the body of the human body. Accordingly, the SQUID sensor module may cover the side of the left chest in order to measure the magnetic field signal of the left ventricle of the heart.

The SQUID sensor module mounting plate 220 may be a circular plate or a rectangular plate bent in a C or L shape. A plurality of SQUID sensor modules 10 and a plurality of heat transfer rods 20 may be arranged in a matrix form. The SQUID sensor module mounting plate may include a curved portion. The curved portion may be arranged to surround the left ventricle of the heart.

The 4K heat shield 240 is disposed to surround the SQUID sensor modules 10 and the SQUID sensor module mounting plate 220 . The 4K heat shield 240 is cooled by the main heat anchor and the Litz wire.

13 is a conceptual diagram illustrating a magnetic field measuring device according to another embodiment of the present invention.

14 is a cross-sectional view illustrating the magnetic field measuring device of FIG. 13 .

13 and 14, the magnetic field measuring device 300 includes an outer container 110; An inner container containing a liquid refrigerant 30 and disposed inside the outer container 110 and including a neck portion 362 having a first diameter and a body portion 364 having a second diameter larger than the first diameter. (360); A SQUID sensor module mounting plate 120 disposed in a space maintained in a vacuum state between the inner container 360 and the outer container 110; A plurality of SQUID sensor modules 10 mounted under the SQUID sensor module mounting plate 120; and a 4K heat shield 140 formed of a conductive mesh disposed to surround the SQUID sensor module mounting plate 120 and the plurality of SQUID sensor modules 10 .

The inner container 360 includes a neck portion 362 into which the baffle insert 150 is inserted; and a body portion 164 having a diameter greater than that of the neck portion. The neck portion 362 may include an inner cylindrical portion 362a and an outer cylindrical portion 362b disposed to surround the inner cylinder. The inner cylinder portion 362a may be separated into auxiliary inner cylinders vertically spaced apart from each other. Column anchors 306a, 306b, and 306c may be respectively inserted between the separated auxiliary inner cylinders.

Each of the heat anchors 306a, 306b, and 306c includes a cylindrical first cylindrical portion 306a'; and a washer-shaped first washer portion 306a″ connected from the center to the outside of the first cylindrical portion 306a′. The outer surface outside the first cylindrical portion 306a' may be screwed to the inner surface of the corresponding auxiliary inner cylinder 362a.

The fixing parts 262d may include a washer-shaped second washer part 362d′ and a cylindrical second cylindrical part 362d″ connected to an inner surface of the second washer part. A pair of fixing parts 262d may be respectively disposed on an inner upper surface and an inner lower surface of the first washer part 306a″ of the heat anchor.

The outer cylindrical portion 362b may include a plurality of auxiliary outer cylindrical portions spaced apart from each other. The auxiliary outer cylindrical portion may be disposed to surround the second cylindrical portion 362d″ of the fixing portion.

A heat shielding film 362c may be disposed between the auxiliary outer cylindrical portion and the auxiliary inner cylindrical portion.

Each of the heat anchors 306a, 306b, and 306c may further include a washer-shaped auxiliary washer portion 306a''' connected inwardly from the center of the first cylindrical portion. The auxiliary washer part 306a''' may include a slit formed in an azimuthal direction. The refrigerant vaporized through the slit may be provided to the condenser 159 through the refrigerant exhaust tube 153 .

15 is a perspective view illustrating a SQUID sensor module according to an embodiment of the present invention.

16 is a perspective view illustrating a detection coil of a differential meter of the SQUID sensor module of FIG. 15;

Referring to Figures 15 and 16, the SQUID sensor module 10 according to an embodiment of the present invention, the detection coils (11a, 11b, 11c) are mounted and a rectangular parallelepiped bobbin having a rectangular cross section (14); a fixing block 12 connected to the bobbin 14 and inserted into and fixed to a hole formed in the SQUID sensor module mounting plate 120; A SQUID printed circuit board 13 mounted on at least one surface among upper side surfaces of the bobbin 14 and including a superconducting quantum interference device (SQUID) sensor 13; and a signal line connection PCB 16 inserted into the fixing block 12 and transmitting a signal detected by the SQUID sensor 13 to an external circuit.

The bobbin 14 includes a lower bobbin 14b having a rectangular parallelepiped shape; an upper bobbin (14a) vertically spaced apart from and aligned with the lower bobbin (14b); and bobbin connection pillars 14c disposed at corners to connect the lower bobbin 14b and the upper bobbin. The bobbin 14 may be integrally formed of a non-magnetic material such as G10 epoxy.

The detection coils 11a, 11b, and 11c are differential meters. The detection coil includes: a first differential meter (11a) disposed on a first side surface (1) of the bobbin having first to fourth side surfaces (1,2,3,4); a second differential meter (11b) disposed on a second side surface (2) adjacent to the first side surface (1) of the bobbin; and a third differential meter 11c disposed on the cross section of the bobbin.

In the case of a differential meter, the differential meter includes a signal coil 11a' and a reference coil 11a''. The signal coil 11a' and the reference coil 11a'' are wound in opposite directions. Accordingly, the differential meter measures the differential value of the magnetic signal. Therefore, most of the uniform external environmental noise is removed, and the magnetic signal generated by the signal source close to the signal coil is canceled relatively little, so that the SNR can be increased.

The signal coil 11a′ of the first differential meter 11a may be disposed on the first side surface 1 of the lower bobbin, and the reference coil may be disposed on the first side surface 1 of the upper bobbin. The signal coil 11a' may pass through the lower bobbin so as to be adjacent to the first side surface 1 .

The signal coil 11b' of the second differential meter 11b is disposed on the second side surface 2 of the lower bobbin, and the reference coil 11b'' is disposed on the second side surface 2 of the upper bobbin. It can be.

The signal coil 11c' of the third differential meter 11c may be disposed to surround the lower surface of the lower bobbin, and the reference coil 11c'' may be disposed to surround the upper bobbin.

The fixing block 12 may be integrally formed of a non-magnetic material such as G10 epoxy. The fixing block 12 may be inserted into a through hole formed in the SQUID sensor module mounting plate 120 and fixed through a nut.

The signal line connection PCB 16 has a rectangular plate shape including a rectangular through hole in the center, and the signal line connection PCB 16 may be coupled to an outer circumferential surface of the fixing block 12 . The signal line connection PCB 16 may include a connector. The connector may be connected to an external circuit through a signal line.

SQUID printed circuit boards 18 may be disposed on each side of the fixing block 12 . The detection coils 11a, 11b, and 11c may be electrically connected to the SQUID sensor 13 through a connection line made of a superconductor material. The connection line may have a Nb material.

The SQUID printed circuit board 18 may include a SQUID sensor 18 and a connector disposed on a PCB board. The SQUID sensor 18 may be in the form of a semiconductor chip.

A signal with a high SNR can be obtained in a magnetic shield room having a lower shielding rate than a magnetometer by using a differential meter. However, since the length of the differential system is much longer than that of the magnetometer, the volume occupied by the differential system also increases, so that the area receiving radiant heat coming from room temperature also increases. This greatly increases the evaporation rate of the low temperature refrigerant. The bobbin of the differential system includes a lower bobbin 14b spaced apart from each other in order to minimize heat capacity, the lower bobbin 14b, and bobbin connecting posts 14c disposed at corners, respectively.

In the above, the present invention has been shown and described with respect to specific preferred embodiments, but the present invention is not limited to these embodiments, and a person having ordinary knowledge in the art to which the present invention pertains claims of the present invention It includes all of the various forms of embodiments that can be implemented within a range that does not deviate from the technical idea.

100: magnetic field measurement device
110: outer container
120: SQUID sensor module mounting plate
140: 4K heat shield
160: inner container

Claims (31)

outer container;
An inner container formed of glass fiber reinforced plastic, containing a liquid refrigerant, disposed inside the outer container, and including a neck portion having a first diameter and a body portion having a second diameter greater than the first diameter;
A space between the inner container and the outer container is maintained in a vacuum state, and a SQUID sensor module mounting plate disposed under the inner container;
a plurality of SQUID sensor modules mounted under the SQUID sensor module mounting plate; and
A magnetic field measuring device comprising a 4K heat shield formed of a conductive mesh disposed to surround the SQUID sensor module mounting plate and the plurality of SQUID sensor modules. According to claim 1,
a main thermal anchor cooled by the refrigerant and disposed on a lower surface of the inner container;
a ring-shaped auxiliary heat anchor coupled to a side surface of the SQUID sensor module mounting plate through the 4K heat shield and fixing the 4K heat shield; and
The magnetic field measuring device further comprises a Litz wire for cooling by connecting the main heat anchor and the auxiliary heat anchor. According to claim 2,
The SQUID sensor module mounting plate has a ring-shaped ring depression on the lower surface of the side,
The SQUID sensor module mounting plate includes at least one connection portion penetrating the SQUID sensor module mounting plate in the ring depression,
The auxiliary heat anchor is coupled to the ring recessed portion and magnetic field measuring device, characterized in that it comprises at least one protrusion protruding to be inserted into the connecting portion. According to claim 3,
The 4K thermal shielding unit;
an upper 4K heat shield disposed on an upper surface of the SQUID sensor module mounting plate; and
A lower 4K heat shield disposed to surround the plurality of SQUID sensor modules;
The auxiliary heat anchor is magnetic field measuring device, characterized in that coupled to the side of the SQUID sensor module mounting plate through the lower 4K heat shield. According to claim 1,
a sensor guide rod mounted on a lower surface of the inner container, extending through the SQUID sensor module mounting plate, and guiding vertical movement of the SQUID sensor module mounting plate; and
The magnetic field measurement device further comprising a; sensor fixing rod mounted on the lower surface of the inner container and fixed to the SQUID sensor module mounting plate. According to claim 1,
The SQUID sensor modules pass through the SQUID sensor module mounting plate and are arranged along a first direction and a second direction,
Each of the SQUID sensor modules extends vertically,
Further comprising a plurality of heat transfer rods extending in parallel with the SQUID sensor modules,
The heat transfer rods pass through the SQUID sensor module mounting plate,
Magnetic field measuring device, characterized in that both ends of the heat transfer rods are respectively connected to the 4K heat shield. According to claim 1,
The SQUID sensor modules are arranged in a matrix form along a first direction and a second direction orthogonal to the first direction,
The SQUID sensor module mounting plate is:
Further comprising a trench extending in the first direction from the SQUID sensor module mounting plate between the SQUID sensor modules arranged in the first direction and the SQUID sensor modules spaced apart from each other in the second direction and arranged in the first direction Magnetic field measuring device, characterized in that for. According to claim 7,
The magnetic field measurement device further comprises a signal line connection hole connected to the trench and arranged at regular intervals in the first direction and penetrating the SQUID sensor module mounting plate. According to claim 8,
The SQUID sensor module mounting plate has a ring-shaped ring depression on the lower surface of the side surface,
The SQUID sensor module mounting plate includes at least one connection portion penetrating the SQUID sensor module mounting plate in the ring depression,
The auxiliary heat anchor includes at least one protrusion that engages with the ring recessed portion and protrudes to be inserted into the connecting portion;
The magnetic field measuring device, characterized in that the trench disposed on the outermost side in the first direction is connected to the connection part. According to claim 1,
The inner container:
a neck into which a baffle insert is inserted; and
Including; a body portion having a diameter greater than the neck portion;
The magnetic field measuring device, characterized in that the neck portion has a double wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder. According to claim 10,
The inner cylinder further includes a plurality of ring protrusions protruding outward of the cylinder,
Thermal anchors engage each of the ring protrusions,
The ring protrusions are disposed spaced apart from each other,
The magnetic field measuring device, characterized in that the outer cylinders are separated from each other with the ring protrusion interposed therebetween. According to claim 11
The neck portion further comprises a heat shielding film disposed between the inner cylinder and the outer cylinder. According to claim 11,
Magnetic field measuring device, characterized in that the outer circumferential surface of the ring protrusion and the inner circumferential surface of the heat anchor are screwed together. According to claim 11,
The heat anchors include first to third heat anchors of a washer shape arranged in order and vertically spaced apart from each other on the outside of the neck,
The first heat anchor is connected to a 120K thermal shield,
The second thermal anchor is connected to an 80K thermal shielding film,
The third heat anchor is connected to a 40K heat shield,
The magnetic field measuring device, characterized in that the 40 K heat shielding film is disposed to surround the 4K heat shield. According to claim 14,
Wherein each of the first to third column anchors includes a plurality of slits extending in a radial direction. According to claim 1,
The inner container:
a neck into which a baffle insert is inserted; and
Including; a body portion having a diameter greater than the neck portion;
a refrigerant exhaust tube disposed on the baffle insert and exhausting the vaporized refrigerant;
a refrigerant injection tube disposed in the baffle insert and injecting refrigerant; and
A condenser connected to the refrigerant exhaust tube and the refrigerant injection tube and condensing the vaporized refrigerant exhausted through the refrigerant injection tube;
The refrigerant exhaust tube and the refrigerant injection tube have a coaxial structure,
The magnetic field measuring device, characterized in that each of the refrigerant exhaust tube and the refrigerant injection tube is a double tube having an inner tube and an outer tube. According to claim 2,
The main column anchor is:
A first heat transfer comprising a first disc formed of oxygen-free copper, a first upper protrusion protruding from a central axis of the first disc to an upper surface, and a first lower protrusion protruding from a central axis of the first disc to a lower surface. wealth;
A second heat transfer comprising a second disc formed of oxygen-free copper, a second upper protrusion protruding from a central axis of the second disc to an upper surface, and a second lower protrusion protruding from a central axis of the second disc to a lower surface. wealth;
A third heat transfer comprising a third disc formed of oxygen-free copper, a third upper protrusion protruding from a central axis of the third disc to an upper surface, and a third lower protrusion protruding from a central axis of the third disc to a lower surface. wealth;
a fourth heat transfer unit formed of oxygen-free copper and including a fourth disc, a fourth upper protrusion protruding from a central axis of the fourth disc to an upper surface, and a plurality of holes on a lower surface from the central axis of the fourth disc;
a first thermal expansion control unit formed of an insulator and inserted between the first disc of the first heat transfer unit and the second disc of the second heat transfer unit; and
A second thermal expansion controller formed of an insulator and inserted between the third disc of the third heat transfer unit and the fourth disc of the fourth heat transfer unit,
The second upper protrusion of the second heat transfer part has a groove for engaging with the first lower protrusion of the first heat transfer part;
The second lower protrusion of the second heat transfer part has a groove for engaging with the third upper protrusion of the third heat transfer part,
The magnetic field measuring device of claim 1, wherein the third lower protrusion of the third heat transfer part has a groove for coupling with the fourth upper protrusion of the fourth heat transfer part. According to claim 17,
The first thermal expansion controller:
a first insulating body having the same diameter as that of the first disc;
a second insulating body part buried in the lower surface of the inner container and having a second diameter larger than the diameter of the first disc; and
A third insulating body having a third diameter smaller than the second diameter,
The third insulating body part is a magnetic field measuring device, characterized in that arranged to surround the outer circumferential surface of the second disc. According to claim 1,
The SQUID sensor module mounting plate includes a curved portion,
The magnetic field measuring device, characterized in that the curved portion is disposed to surround the left ventricle of the heart. According to claim 1,
The inner container:
a neck into which a baffle insert is inserted; and
Including; a body portion having a diameter greater than the neck portion;
The neck portion includes an inner cylinder portion and an outer cylinder portion disposed to surround the inner cylinder portion,
The inner cylinder is divided into auxiliary inner cylinders arranged vertically spaced apart from each other,
Each of the heat anchors is a magnetic field measuring device, characterized in that each inserted between the separated auxiliary inner cylinders. According to claim 20,
Each of the heat anchors:
A first cylindrical portion having a cylindrical shape; and
A first washer portion having a washer shape connected to the outside from the center of the first cylindrical portion,
The magnetic field measuring device, characterized in that the outer surface outside the first cylindrical portion is screwed to the inner surface of the corresponding auxiliary inner cylinder. According to claim 21,
Further comprising fixing parts including a washer-shaped second washer part and a cylindrical second cylindrical part connected to an inner surface of the second washer part,
A pair of fixing parts are magnetic field measuring devices, characterized in that disposed on the inner upper surface and the inner lower surface of the first washer part of the heat anchor, respectively. 23. The method of claim 22,
The outer cylindrical portion includes a plurality of auxiliary outer cylindrical portions disposed spaced apart from each other,
The auxiliary outer cylindrical portion is disposed to surround the second cylindrical portion of the fixing portion,
A magnetic field measuring device, characterized in that the heat shielding film is disposed between the auxiliary outer cylinder and the auxiliary inner cylinder. According to claim 23,
Each of the heat anchors further includes a washer-shaped auxiliary washer portion connected inwardly from the center of the first cylindrical portion,
The auxiliary washer part magnetic field measuring device characterized in that it comprises a slit formed in the azimuth direction. According to claim 1,
Each of the SQUID sensor modules
A bobbin in the shape of a rectangular parallelepiped having a rectangular cross section and equipped with a detection coil;
a fixing block connected to the bobbin and fixed by being inserted into a hole formed in the SQUID sensor module mounting plate;
A SQUID printed circuit board mounted on at least one surface among upper side surfaces of the bobbin and including a superconducting quantum interference device (SQUID) sensor; and
Magnetic field measuring device characterized in that it comprises a signal line connection PCB inserted into the fixed block and transmitting the signal detected by the SQUID sensor to an external circuit. According to claim 25,
The detection coil is a differential meter,
The detection coil is:
a first differential meter disposed on a first side of the bobbin;
a second differential meter disposed on a second side surface adjacent to the first side surface of the bobbin; and
A magnetic field measuring device comprising a third differential meter disposed on the lower surface of the bobbin.
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